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Hoe hanteer migrerende ganse orkane?

Hoe hanteer migrerende ganse orkane?


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Ek woon aan die ooskus van die Verenigde State, waar ons in orkaanseisoen is. Hierdie week tydens my oggendfietsritte in Charlotte, Noord-Carolina, het ek migrerende Kanadese ganse gesien.

Ek is nuuskierig of migrerende ganse enige aanpassings het om orkane te bespeur en te hanteer? Hanteer hulle dit soos enige ander reën en wag dit uit of is daar waarnemings dat hulle 'n storm vermy?

Hier is die reeks van die Canada Goose.


Hoe oorleef voëls storms en ander harde weer?

Oorlewing in die wilde, wrede, genadelose wêreld is 'n matige ding. Daar is roofdiere wat jou probeer eet, patogene wat jou probeer besmet, mededingers wat jou probeer slaan. Dit is waarlik, soos Alfred Lord Tennyson geskryf het, "Natuur, rooi in tand en klou." By hierdie lys van potensieel sterflike gevare is ongure weer. Hewige storms kan baie diere doodmaak, en voëls is geen uitsondering nie. Maar duidelik kan voëls hierdie storms oorleef, anders sou daar min voëls oor wees. Selfs die harde winter wat ons sopas beleef het, is gevolg deur 'n uitbarsting van sang van ons geveerde vriende. So hoe doen hulle dit?

Die antwoord is in twee dele. Die eerste kan opgesom word as "ligging, ligging, ligging." Daar is 'n paar voordele daaraan verbonde om klein te wees, en om voordeel te trek uit mikrohabitatte is een. Stormsterk winde kan ons hoede opeis en ons sambrele vernietig, maar baie voëls kan skuiling soek aan die lugkant van bome of diep binne-in dik heinings. Die afname in windspoed in hierdie mikrohabitatte kan groot wees. So so lank as wat die voëls bly sit, word hulle nie eintlik baie deur die wind getref nie. Hierdie gebiede kan ook help om voëls droog te hou, selfs in 'n stormagtige reënbui.

Mikrohabitatte kan geweldig help met koue temperature. Al kan dit bitter koud wees op ons neusvlak etlike voet bo die grond, kan die temperatuur baie grade warmer wees net 'n paar duim bo die grond. Hierdie effek word selfs verder vergroot wanneer die son skyn. Probeer gedurende 'n bitter nare dag vir 'n paar minute op die grond lê, veral agter iets wat die wind breek. Jy sal ontdek dat toestande geweldig verbeter. Trouens, baie van die oorblywende ongemak sal waarskynlik afkomstig wees van die koue, nat grond waarop jy lê.

Wat my by die tweede manier bring waarop voëls storms oorleef—voorbereiding.

Voorbereiding kom in twee dele. Die eerste is voorbereiding deur evolusie. Voëls is uitstekend aangepas om in slegte weer te oorleef. Dit begin by die voete. Alhoewel daardie koue, nat grond vir jou ongemaklik is, is dit nie besonder ongemaklik vir 'n voël nie. Daardie spinnetjies beentjies het 'n wonderlike aanpassing wat teenstroomwisseling genoem word. Ons verloor meestal hitte, en voel dus koud, van warm bloed in die vel wat hitte na die koue lug uitstraal. Die verlies aan hitte bring koue bloed terug na ons liggaam se kern, wat ons selfs meer verkoel.

By voëls gaan die are met warm bloed wat na die voete loop reg langs die koue bloed wat in die are loop terug na die liggaam. Met hierdie reëling gee die warm bloed in die are hitte deur na die koue bloed in die are voordat die bloed selfs die voete bereik. Die hitte word dus na die liggaam teruggestuur en lei tot koue bloed in die voete. Koue voete verloor baie min hitte aan die koue grond.

’n Tweede aanpassing is vere. Daar is 'n rede hoekom ons donsbaadjies begeer vir hul warmte. Die vere is uitstekend in staat om lug vas te vang. Hierdie vasgevange lug verhoed dat koue lug na die vel sirkuleer en daardeur baie effektiewe isolasie skep—en hoe donsiger die vere, hoe beter is die isolasie. Voëls kan die hoeveelheid "pluis" in hul vere aanpas. Klein voëls wat in die Arktiese gebied woon, kan hul vere voldoende pluis om temperature baie dosyne grade onder nul Fahrenheit te oorleef.

Om op te som, voëloorlewing is afhanklik van die vind van 'n voldoende mikrohabitat, vermindering van aktiwiteit, en die gebruik van vere en teenstroom-uitruiling om hitteverlies te minimaliseer. Die onaktiwiteit wat nodig is om hierdie strategieë te optimaliseer, beteken egter dat die voëls nie vir kos kan soek nie.

Dit bring ons by die laaste manier waarop voëls voorberei vir storms. Hulle moet die hoeveelheid gestoorde energie verhoog om hulle deur die tydperk van onaktiwiteit te kry. Hulle doen dit meestal deur vet. Daar is 'n paar verslae van voëls wat toeneem namate 'n storm nader kom. Dit blyk dat ten minste sommige voëls subtiele veranderinge in lugdruk kan bespeur, wat kan dui op 'n naderende storm, en hulle probeer dadelik om soveel as moontlik kos te kry. Hoe meer vet 'n voël het, hoe groter kans het dit om te oorleef.

'n Bekende vroeë voorbeeld is in 1899 gerapporteer deur Hermon Carey Bumpus, 'n bioloog wat van 1915 tot 1919 as president van Tufts gedien het. Hy het gevind dat slegs die grootste, en vermoedelik vetste, huismossies 'n groot storm oorleef het. Dit behoort intuïtief sin te maak. Hoe beter jou energiereserwes, hoe beter is jou kanse om 'n storm te oorleef. So hoekom is alle voëls nie so vet as wat hulle moontlik kan wees nie? Die antwoord is daardie lastige roofdiere wat aan die begin bespreek is. 'n Vet voël is ook 'n stadige voël, en 'n baie makliker teiken. Op die ou end is die hoeveelheid vet wat 'n voël dra 'n afweging tussen so min as moontlik om rats te bly en roofdiere te vermy en soveel as moontlik om 'n buffer te bied om gure weer te oorleef. Hierdie tipe afruil is algemeen onder wilde diere.

So die volgende keer wanneer 'n nare storm deurrol, wonder oor die vindingrykheid van die voëls, en jubel in hul liedjies wanneer hulle weer opduik sodra die storm, "vol klank en woede," verby is.


Migrerende Arktiese Ganse is verward, uitgeput deur stygende temperature

Brandganse het hul migrasie na hul broeiplekke bespoedig weens warmer Arktiese temperature.

Brandganse migreer elke lente meer as 1 800 myl van Nederland en Noord-Duitsland na hul broeiplekke in dele van Rusland bo die Noordpoolsirkel.

Die reis noord neem gewoonlik sowat 'n maand, en die ganse maak verskeie stops langs die pad om te eet en vet te maak voordat hulle hul eiers lê, sê Bart Nolet van die Nederlandse Instituut vir Ekologie en die Universiteit van Amsterdam.

Maar daardie migrasiepatroon is besig om te verander, aangesien vinnig stygende temperature gelei het tot vroeëre bronne in die Arktiese gebied.

So Nolet se span het tientalle brandganse opgespoor om uit te vind hoe hulle deur die vroeëre sneeusmeltings geraak word. Hul resultate is in 'n nuwe studie in Current Biology gepubliseer.

Een groot ding het nie verander nie: watter tyd van die jaar begin die ganse noordwaarts trek. En dit is 'n probleem.

Die Tweerigting

Wetenskaplikes voorspel dat koningspikkewyne groot bedreigings in die gesig staar as gevolg van klimaatsverandering

"Hulle vertrek eintlik van die oorwinteringsgebiede rondom dieselfde datum, ongeag of dit vroeg of laat lente in die Arktiese gebied is," sê Nolet. Dit is waarskynlik omdat die ganse "nie kan voorspel wat die weer is of wat die seisoen daarbo is vanaf 3 000 kilometer afstand nie."

Histories het die ganse net nadat die sneeu gesmelt het aangekom en hul eiers dadelik gelê. Dit gee plante tyd om te begin groei sodat die gansies kan baat vind by wat bekend staan ​​as 'n "voedselpiek."

Deesdae is die weer in dele van die reis noord warmer as wat dit was en dit lyk asof die voëls besef dat hulle laat raak. Hulle begin versnel - baie.

’n Reis wat die brandganse gewoonlik ’n maand neem, neem nou sowat ’n week, het die navorsers bevind. Dit is 'n marathon: "Hulle vlieg byna ononderbroke van die oorwinteringsgebiede na hul broeiplekke," sê Nolet.

Al maak hulle tyd op pad op, kan die uitgeputte ganse nie dadelik eiers lê nie, want hulle het tyd nodig om te vreet en te herstel - nog sowat 10 dae.

Diere

Lang uitgestorwe Gibbon gevind in graf van Chinese keiser se ouma

Dit beteken die gansies kan nie meer daardie smaaklike en voedsame "kospiek" geniet nie, soos Nolet dit gestel het. In plaas daarvan, "wanneer die eiers uitbroei, verswak die kos reeds in kwaliteit, en wat ons gevind het, is dat gansies minder goed oorleef in so 'n vroeë jaar as wat hulle normaalweg doen."

Kortom, stygende Arktiese temperature beteken dat trekbroodganse nie sinchroniseer is met van hul beste voedselbronne nie, wat beteken dat minder van hul kuikens hul vroeë maande oorleef.

So hoekom vertrek die voëls nie net vroeër vir hul reis noord nie? Nolet sê hulle dink hierdie spesie neem waarskynlik sy leidraad om te vertrek gebaseer op hoe lank die dagligure duur, eerder as die temperatuur sowat 1 800 myl weg.

Maar die toekoms van die brandgans kan afhang van sy vermoë om by die nuwe werklikheid aan te pas en vroeër te vertrek. Gelukkig, sê Nolet, is die voël 'n "buigsame" spesie wat in groepe reis, wat dit meer waarskynlik maak dat as 'n paar vroeër begin vertrek, ander sal volg.

Die veranderende klimaat kan meer problematies wees vir ander spesies soos kusvoëls, sê hy, waar dalende bevolkings "moontlik te make het met die wanverhouding waaroor ons praat tussen voedselpiek en uitbroei van eiers."

Oor die algemeen sal klimaatsverandering waarskynlik hierdie soort wanverhouding skep vir diere wat lang afstande migreer. Dit is moeiliker vir hulle om aan te pas, sê Nolet, wanneer hulle 'n deel van die jaar in 'n totaal ander klimaat deurbring.


Voëlmigrasie: definisie, tipes, oorsake en leidende meganismes

Die woord “migrasie” kom van die Latynse woord migrara wat beteken om van een plek na 'n ander te gaan. Baie voëls het die inherente kwaliteit om van een plek na 'n ander te beweeg om die voordele van die gunstige toestand te verkry.

By voëls beteken migrasie tweerigtingreise—voorwaartse reis van die ‘huis’ na die ‘nuwe’ plekke en terugreis van die ‘nuwe’ plekke na die ‘huis’. Hierdie verskuiwing vind plaas gedurende die spesifieke tydperk van die jaar en die voëls volg gewoonlik dieselfde roete. Daar is 'n soort ‘interne biologiese klok’ wat die verskynsel reguleer.

Volgens L. Thomson (1926) kan voëlmigrasie beskryf word as “veranderinge van habitat wat periodiek herhalend en verander&shinerend in rigting, wat geneig is om te alle tye optimale omgewingstoestande te verseker”.

Voëlmigrasie is 'n min of meer gereelde, uitgebreide bewegings tussen hul broeistreke en hul oorwinterende streke.

2. Tipes voëlmigrasie:

Alle voëls migreer nie, maar alle spesies is onderhewig aan periodieke bewegings van wisselende omvang. Die voëls wat in die noordelike deel van die halfrond woon, het die grootste migra- en skutkrag.

(iii) Hoogte of Vertikaal,

(i) Latitudinale migrasie:

Die breedte-migrasie beteken gewoonlik die beweging van noord na suid, en omgekeerd. Die meeste voëls leef in die landmassas van die noordelike gematigde en subarktiese sones waar hulle gedurende die somer fasiliteite kry vir nes en voeding. Gedurende die winter beweeg hulle suidwaarts.

’n Omgekeerde maar mindere beweging vind ook in die suidelike halfrond plaas wanneer die seisoene verander. Koekoek broei in Indië en bring die somer by Suidoos-Afrika deur en lê dus 'n afstand van sowat 7250 km af.

Sommige tropiese voëls migreer gedurende reënseisoen na die buitenste trope om te broei en terug te keer na die sentrale trope in droë seisoen. Baie mariene voëls maak ook aansienlike migra­tion. Puffinus (Groot skeerwater) broei op klein eilande en migreer in Mei tot by Groenland en keer na 'n paar maande terug.

Dit dek 'n afstand van 1300 km. Pikkewyne migreer deur te swem en dek 'n aansienlike afstand van 'n paar honderd myl af. Sterna paradisaea (Arktiese sterretjie) broei in die noordelike gematigde streek en migreer na die Antarktiese sone langs die Atlantiese Oseaan. Daar is waargeneem dat Sterna 'n afstand van 22 500 km aflê tydens migrasie!

(ii) Longitudinale migrasie:

Die longitudinale migrasie vind plaas wanneer die voëls van oos na wes migreer en omgekeerd. Spreeus (Sturnus vulgaris), 'n inwoner van Oos-Europa en Wes-Asië migreer na die Atlantiese kus. Kalifornië meeue, 'n inwoner en ras in Utah, migreer weswaarts na die winter in die Stille Oseaan-kus.

(iii) Hoogtemigrasie:

Die hoogtemigrasie vind plaas in bergagtige streke. Baie voëls wat die bergpieke bewoon, migreer gedurende die winter na lae lande. Goue plevier (Pluvialis) begin vanaf Arktiese toendra en gaan op na die vlaktes van Argentinië wat 'n afstand van 11 250 km aflê (Fig. 9.54).

Voëls migreer óf in swerms óf in pare. Swaeltjies en ooievaars migreer 'n afstand van 9650 km van Noord-Europa na Suid-Afrika. Ruff broei by Siberië en reis na Groot-Brittanje, Afrika, Indië en Ceylon en reis dus 'n afstand van 9650 kilometer af.

Al die lede van 'n groep voëls neem nie aan migrasie deel nie. Slegs verskeie lede van 'n groep neem aan migrasie deel. Blue Jays van Kanada en die noordelike deel van die Verenigde State reis suidwaarts om te meng met die sittende bevolkings van die Suidelike State van V.S.A. Koetse en lepelsnawels (Platalea) van ons land kan 'n voorbeeld van gedeeltelike migrasie wees.

(v) Totale migrasie:

Wanneer al die lede van 'n spesie aan die migrasie deelneem, word dit totale migrasie genoem.

(vi) Swerwerige of onreëlmatige migrasie:

Wanneer sommige van die voëls na 'n kort of lang afstand versprei vir veiligheid en voedsel, word dit rondloper of onreëlmatige migrasie genoem. Reiers kan die voorbeeld van rondloper of onreëlmatige migrasie wees. Ander voorbeelde is swart ooievaar (Ciconia nigra), Glansibis (Plegadis falcinellus), gevlekte arend (Aquila clanga), en byvreter (Merops apiaster).

(vii) Daaglikse migrasie:

Sommige voëls reis daagliks van hul neste af deur die invloed van omgewingsfaktore soos temperatuur, lig en humiditeit. Voorbeelde is kraaie, reiers en spreeus.

(viii) Seisoenale migrasie:

Sommige voëls migreer op verskillende seisoene van die jaar vir kos of broei, wat seisoenale migrasie genoem word, bv. koekoeke, windswaels, swaeltjies, ens. Hulle migreer van die suide na die noorde gedurende die somer. Hierdie voëls word somerbesoekers genoem. Weereens is daar voëls soos sneeugors, rooivlerk, oewerkiewiet, grysplevier ens. wat gedurende die winter van noord na suid migreer. Hulle word winterbesoekers genoem.

Nagtelike en Dagvlug:

(i) Dagmigrasie:

Baie groter voëls soos kraaie, rooibokke, swaeltjies, valke, jaye, blou voëls, pelikane, kraanvoëls, ganse, ens. migreer gedurende die dag vir kos.

Hierdie voëls word dagvoëls genoem en migreer gene en shiraal in swerms.

(ii) Nagvoëls:

Sommige klein voëls van passerine-groepe soos mossies, sangers, ens. migreer in duisternis, wat nagvoëls genoem word. Die duisternis van die nag gee hulle beskerming teen hul vyande.

3. Oorsake van Migrasie:

Die meeste spesies voëls migreer min of meer op skedule en volg die roetes op 'n gereelde manier. Die werklike oorsaaklike faktore wat die verloop en rigting van migrasie bepaal, is nie duidelik bekend nie.

Die volgende faktore kan verband hou met die probleme van migrasie:

i. Instink en Gonadale verander:

Dit word algemeen aanvaar dat die impuls om by voëls te migreer moontlik instinktief is en die migrasie na die broeiplekke word geassosieer met gonadale veranderinge.

ii. Skaarste aan kos en daglengte:

Ander faktore, nl. skaarste aan voedsel, verkorting van daglig en toename in koue, word geglo om migrasie te stimuleer. Migrasie by voëls hang af van twee belangrike faktore—stimulus en leiding.

Daar word geglo dat skaarste aan voedsel en val van daglig endokriene veranderinge veroorsaak wat voëlmigrasie inisieer.

Die toename van daglengte (Photoperiodism) veroorsaak voëlmigrasie’s. Die daglengte beïnvloed pituïtêre en pineale kliere en het ook groei van gonades veroorsaak wat geslagshormone afskei wat die stimulus vir migrasie is. In Indië, Siberiese kraanvoël, ganse, swane wat van Sentraal-Asië, Himalajas kom, begin vanaf Maart en verder terugkeer met die toename van die daglengte.

iv. Seisoenale variasie:

Die noord-na-suid-migrasies van voëls vind plaas onder stimulus van die interne toestand van die gonades wat deur seisoenale variasie beïnvloed word.

Die eksperimente van Rowan met Juncos (somerbesoeker aan Kanada) het vasgestel dat lig 'n belangrike rol speel in die ontwikkeling van gonades, wat 'n indirekte rol op migrasie speel. As die gonades regressie ondergaan, word die drang na migrasie nie gevoel nie. Die seisoenale veranderinge in beligting blyk dus 'n deurslaggewende faktor te wees vir die bepaling van migrasie.

Ten spyte van al hierdie voorstelle is dit nie duidelik hoe voëls - deur opeenvolgende generasies - dieselfde roete volg en dieselfde plek bereik nie. Die instinktiewe gedrag soos migrasie, teling, vervelling is fasiese gebeurtenisse in die jaarlikse siklus wat moontlik deur die endokriene sisteem beheer word. By alle trekvoëls vind ophoping van vet plaas vir ekstra brandstof tydens langdurige vlug in migrasie.

4. Leidende meganismes in voëlnavigasie:

Vir meer as 'n eeu het die hemelnavigasies van voëls die voëlkenners gefassineer. Verskillende verduidelikings is gevorder om te verduidelik hoe voëls navigeer. Dit is moeilik om te veralgemeen oor die wyses van oriëntasie en navigasie in migrasie. Die verskillende groepe voëls met verskillende maniere van bestaan ​​het verskillende maniere ontwikkel om hul weg van een plek na 'n ander te vind (Pettingill, 1970).

Die ander redes kan wees:

Trekvoëls word gulsig en vet word in die onderhuidse gebied van die liggaam neergelê. Die vetneerlegging speel 'n belangrike rol in die migrasie van voëls. Voëls, dié wat oor 'n lang afstand migreer, behou genoeg vet wat energie verskaf in hul moeilike reis en die voëls help om hul bestemming te bereik, volgens 'n spesifieke roete. Na vetneerlegging word rusteloosheid (Zugunruhe) onder voëls vir migrasie gesien.

Oorgeërfde instink:

Voëls wat aan migrasie deelneem of 'n min of meer bepaalde doelwit volg, besit klaarblyklik 'n oorgeërfde instink. Beide die rigting en die doel moet in die voël’ se genetiese kode ingeplant gewees het wanneer 'n bevolking kan aanpas by 'n bepaalde plek of omgewing.

Ervare Lei die kudde:

Die teorie word soms gevorder dat ou en ervare voëls die pad lei en daardeur die hele roete lei en die hele roete vir die jonger geslag wys. Dit kan van toepassing wees op sommige voëls soos swane, ganse en kraanvoëls omdat hulle in swerms vlieg, maar nie van toepassing op alle spesies waar oud en kleintjies op verskillende tye migreer en hoofsaaklik kleintjies voor die volwassene begin nie.

Werner Ruppell van Duitsland, 'n toonaangewende eksperiment op voëlmigrasie, het gevind dat Spreeus van Berlyn hul pad terug vind na hul broeiplekke van ongeveer 2 000 km weg. ’n Seevoël met die naam Manx skeerwater wat van die westelike kus van Engeland versamel is nadat dit per vliegtuig na Boston gevlieg is, is binne 12 dae terug in sy nes in Engeland gevind.

Die shearwa­ter het sy eie pad sowat 4940 km oor die onbekende Atlantiese Oseaan gevlieg! Die gold­en plevier van Noord-Amerika migreer van sy winterhuis in die Hawaiiaanse eilande na sy broeiplek in Noord-Kanada.

Hierdie voël het nie gewebde voete nie en dit is heel natuurlik dat hy vir etlike weke oor duisende kilometers see moet vlieg om sy bestemming te bereik. Die voëls het wonderlike navigasie- en oriëntasievermoë om selfs onder vreemde omstandighede hul bestemming te vind.

Daar is baie teorieë oor die verskynsel van migrasie by voëls.

Verskeie teoretici stel voor dat voëls deur 'n aantal agentskappe gelei word:

a. Aarde se magnetiese veld—as die leidende faktor:

Sommige voëlkenners het geglo oor die bestaan ​​van 'n “magnetiese sin” as die belangrike faktor in die krag van “geografiese oriëntasie”. Die teorie is so vroeg as 1885 bedink, maar uitgevoer deur Yeagley in 1947 en 1951. Yeagley het voorgestel dat voëls sensitief is en gelei word deur die aarde se mag&sinetiese veld.

Die Coriolis-krag wat voortspruit uit rotasie van die aarde speel die leidende rol in migrasie van voëls. Die basiese vraag van die teorie kan gevra word - “kan voëls sulke klein verskille in die aarde se magnetiese veld opspoor en kan hierdie kragte voëls se gedrag beïnvloed?”

Pogings om te demonstreer deur eksperimentele bewyse het nie Yeagley’ se eksperiment ondersteun nie. Eksperimente, waarin die aarde se magnetiese veld verander is, het geen effek gehad op die rigting wat die voëls onderneem het nie.

b. Son—die leidende middel in daaglikse migrasie:

Die konsep dat voëls deur die posisie van die son gelei word, is deur Gustav Kramer in Duitsland en G. V. T. Matthews in Engeland bevorder. Hulle het deur intensiewe eksperimente getoon dat die posduiwe en baie wilde voëls die son as die kompas gebruik en dat hulle 'n ‘tydsin’ of ‘interne klok’ het wat hulle in staat stel om rekening te hou met die beweging van die son oor die lug.

Kramer (1949, 1957, 1961) het eksperimente op Spreeus (dagtrekkers) uitgevoer en getoon dat hierdie voëls die son gebruik om hul trekkoers te bepaal. Wanneer die lug helder bly, slaag die Spreeus daarin om die regte rigting in te slaan.

As die lug bewolk bly, raak hulle verward en versuim om hulself te oriënteer. Meganiese plasing van 'n spieël wat strale van die son afbuig, lei tot 'n aansienlike afwyking van oriëntasie tot 'n voorafbeskroomde mate. Die eksperimente van Kramer en ander het nie daarin geslaag om die navigasie en oriëntering van nagmigrante te verduidelik nie. Hierdie aspek is uitvoerig en skugter uitgewerk deur E.G.F. Sauer (1958).

c. Sterre—die leidende agent in nagtelike migrasie:

Die sangers en baie ander voëls oriënteer hulle tydens navigasie deur die son gedurende die dag. Maar die sangers sowel as baie ander voëls navigeer hoofsaaklik in die nag. Watter soort stelsel gebruik hierdie voëls na die paadjies tydens navigasie in die nag?

Sauer het eksperimente op witkeelsangers uitgevoer om 'n insig oor die probleem te gee. Sauer het die voëls in 'n hok geplaas wat in 'n planetarium geplaas is met 'n kunsmatige replika van die natuurlike lug. Toe die lig van die planetarium swak verlig was, d.w.s. wanneer die sterre nie sigbaar was nie, het die oorlogsmanne nie daarin geslaag om hulself te oriënteer nie.

Toe die beligting beter was en die planetariumhemel ooreenstem met die natuurlike naghemel, het die voëls die regte rigting opgevolg. Dit is ook deur Sauer getoon dat 'n sanger wat sy lewe in 'n hok deurgebring het (d.w.s. nooit in die natuurlike lug navigeer het nie) 'n aangebore vermoë het om die sterre te volg om langs die gewone roete te navigeer wat die lede van die spesie volg.

Sauer het voorgestel dat die sangers oor oorerflike meganismes beskik om hulleself deur die sterre te oriënteer tydens nagtelike migrasie. Die sanger kan die rigting perfek aanpas op die breedtegraad.

Baie werkers het voorstelle gemaak dat die konfigurasie van die kuslyn moontlik help met navigasie, maar Sauer het die idee ontwrig en gepleit dat die voëls uitsluitlik deur die sterre gedurende die nag gelei word.

d. Die ‘kompas’ en die ‘interne klok’ in voëlmigrasie:

Dit is 'n bekende feit dat miljoene voëls in elke herfs na hul winter ‘huis’ vlieg. Sodoende dek hulle dikwels duisende kilometers van hul geboorteland ‘huis’ af. In die volgende lente keer hulle weer terug na hul broeiplekke. Dit is 'n gereelde bio- en skaalverskynsel in die voëllewe.

Daar is vasgestel dat die jong voëls wat tydens migrasie gevang word, wanneer hulle daarna vrygelaat word, presies die oorspronklike roete volg wat hul onversteurde maats gevolg het. Hierdie verskynsel het die teenwoordigheid van 'n soort ‘kompas’ voorgestel wat die voëls tydens navigasie gebruik.

Maar Kramer’s eksperiment het 'n leidraad tot die probleem. Die posisie van die son is noodsaaklik om die navigasiepaaie te beheer. Gedurende die dag word die posisie van die son in die lug van oos na wes via die suide verander. Ten spyte van sulke veranderinge het voëls in dieselfde rigting probeer navigeer. Dit beteken dat hulle die inherente vermoë het om toepaslike voorsiening te maak vir die tyd van die dag.

Hoe weet die voëls die tyd van die dag? Hulle het moontlik 'n ingeboude tyd­keeping meganisme (interne klok) wat gesinchroniseer is met die aarde’s rotasie. Die ‘interne klok’ kan gemaak word om te sinchroniseer met eksterne gebeure.

Die bestaan ​​van biologiese horlosies is 'n pro&hyperty van lewende organismes. Dit is nie beperk tot diere nie, dit word in plante en selfs in sim­ple-selle ook aangetref. Dit is 'n algemene ervaring dat as ons in die gewoonte is om elke dag op 'n spesifieke tyd op te staan, ons gereeld op dieselfde tyd wakker word. Boonop het baie van ons liggaamsfunksies 'n ritme van hul eie. Hierdie word moontlik beheer deur 'n ‘interne klok’ waarvan ons normaalweg onbewus is.

Telemetrie beteken metodes om die beweging van voëls of ander trekdiere op te spoor deur radio te gebruik. Dit is die mees belowende metode wat toegepas is om die roete van voël’s migrasie op te spoor. Die metode bestaan ​​uit die aanheg van 'n klein radiosender, wat ongeveer 2-3 g weeg. wat periodieke seine of “pieps” stuur.

Die miniatuur-sender kan op voëls geplaas word en dit belemmer nie vlug nie en die seine kan opgespoor word deur middel van 'n ontvangstel wat op voertuie of vliegtuie gemonteer is wat die roetes van trekvoëls kan opspoor.

Alhoewel daar 'n paar beperkinge van telemetrie is, maar hierdie tegnologie gee aanmoedigende en bemoedigende resultate. Meer onlangs is navorsers grootliks besig om die roetes van die trekvoëls op te spoor met behulp van satelliete en radaropsporingsinstrumente.

5. Nadele van Voëlmigrasie:

i. Baie jongmense is nie in staat om die bestemming te bereik nie, want hulle sterf tydens die aaneenlopende en vermoeiende reis.

ii. Skielike veranderinge in die klimaat soos storms en orkane, sterk windstroom, mis is die oorsake vir die dood van 'n aansienlike aantal migrante.

iii. Soms veroorsaak mensgemaakte hoë toere en ligte huise die dood van trekvoëls.

iv. Die mens self is verantwoordelik vir die dood van die migrante. Hulle skiet op hierdie arme voëls net vir hul eie ontspanning en vermaak.


Dit’s in die voete: hoe Kanada ganse warm bly tydens koue snaps

MEDICINE HAT, AB - Met die grootste deel van Suid-Alberta onder 'n uiterste koue waarskuwing, sal inwoners waarskynlik binnenshuis stroom om warm te bly.

Maar 'n sekere groep plaaslike inwoners kan in die buitelug oorleef, en selfs gaan swem, wanneer die kwik duik.

Kanadaganse kan gesien word waar hulle rondom Medicine Hat hang en op koue dae op die Suid-Saskatchewan-rivier dryf.

Dit is omdat ganse sekere biologiese kenmerke het wat hulle warm hou. Jo-Anne Reynolds, ’n biologie- en dierkunde-instrukteur by Medicine Hat College, het gesê hul donserige donsvere reguleer hul kerntemperatuur.

“Hulle vere is natuurlik baie warm. Hulle dra in wese 'n donsjas omdat hulle so baie dons onder hul vere het, so dit hou hul lywe warm,” het Reynolds gesê.

Nog 'n meer subtiele kenmerk is die hoofrede wat verhoed dat hul voete aan die ys vasklou – 'n teenstroom bloedsirkulasiestelsel. Reynolds het verduidelik hierdie stelsel werk deur koue en warm bloed uit te ruil.

"Wat in wese gebeur, is dat warm bloed afgekoel word soos dit afkom [na hul voete], so dit is koel teen die tyd dat dit hul voete bereik. Die koel bloed sal opkom en weer sy hitte deel,” het Reynolds gesê, “sodat hulle hul voete net bo vriespunt kan hou.”

In baie gevalle kan Kanadaganse hul voete onder hul lywe insteek, maar Reynolds het bygevoeg dat hierdie spesiale biologiese kenmerk help om die verlies van liggaamshitte te voorkom, en hul voete teen rypbyt veilig hou.

Kanadaganse is toegerus om koue snappe te oorleef, maar sommige bevolkings migreer. Reynolds het gesê die besluit om te bly of te vertrek sal glo grootliks afhang van die voedselvoorraad.

"As hulle uitgaan na die lande om te voed en die lande is bedek met sneeu, is dit 'n probleem vir hulle," het Reynolds gesê.


Hardloopganse gee insig in lae suurstofverdraagsaamheid

Navorsers het getoets hoe goed die ganse oefening in verminderde suurstofomgewings kan hanteer deur die toestande van Mount Everest in 'n duidelike boks te simuleer en dan die voëls so vinnig as moontlik op 'n trapmeul in die boks te laat hardloop. Krediet: Nyambayar Batbayar

’n Nuwe studie oor hoe die wêreld se hoogste vlieënde voël, die staafkopgans, in staat is om op uiterste hoogtes te oorleef, kan toekomstige implikasies hê vir lae suurstof mediese toestande by mense.

’n Internasionale span wetenskaplikes het onlangs die staafkopgans opgespoor terwyl dit oor die Himalajas migreer het. Nou het hulle gewys hoe hierdie voëls dit kan verdra om teen topspoed te hardloop terwyl hulle net 7% suurstof inasem.

Oefen op hoë hoogte is 'n massiewe uitdaging aangesien die lug bo-op die hoogste berge slegs uit 7% suurstof bestaan, vergeleke met 21% op seevlak. Dit is hoekom menslike klimmers dikwels aanvullende suurstof gebruik wanneer hulle die wêreld se hoogste pieke beklim.

Dr Lucy Hawkes van die Universiteit van Exeter het die studie gelei, saam met kollegas Dr Charles Bishop (Bangor Universiteit) en prof. Pat Butler (Universiteit van Birmingham). Hulle het getoets hoe goed die ganse oefening in verminderde suurstofomgewings kan hanteer deur die toestande van Mount Everest in 'n duidelike boks te simuleer en dan die voëls so vinnig as moontlik op 'n trapmeul binne die boks te laat hardloop.

Hulle het ontdek dat die ganse 'n merkwaardige verdraagsaamheid het vir lae suurstoftoestande – in rus en terwyl hulle vir 15 minute op topspoed geoefen het – teen suurstofvlakke wat die meeste mense heeltemal onbeweeglik sou maak. Die navorsers het ook die eksperimente met die brandgans, wat op seevlak migreer, gedoen en gevind dat hulle nie dieselfde vermoë in lae suurstoftoestande het nie.

Dr Lucy Hawkes, van die Sentrum vir Ekologie en Bewaring aan die Universiteit van Exeter se Penryn-kampus, het gesê: "Dit kom blykbaar alles neer op hoeveel suurstof staafkopganse aan hul hartspiere kan verskaf. Hoe meer hulle kan voorsien, die vinniger kan hulle hul harte klop en die toevoer van suurstof na die res van die liggaam aan die gang hou.Dit dui daarop dat ander spesies, insluitend mense, meer beperk word deur wat ons harte kan doen as deur hoe fiks die res van ons spiere op hoogte is ."

Dr Hawkes, voorheen van die Bangor Universiteit, het bygevoeg: "Die groter implikasies van hierdie bevindings is vir lae suurstof mediese toestande by mense, soos hartaanval en beroerte - wat voorstel watter aanpassings kan help om probleme in die eerste plek te voorkom en om te leer hoe diere dit reggekry het. om werklik ekstreme omgewings te hanteer."

’n Internasionale span wetenskaplikes het onlangs die staafkopgans opgespoor terwyl dit oor die Himalajas migreer het. Nou het hulle gewys hoe hierdie voëls dit kan verdra om teen topspoed te hardloop terwyl hulle slegs 7% suurstof inasem Krediet: Nyambayar Batbayar

Kroegkopganse en brandganse onderneem soortgelyke langafstandtrekvlugte tussen broei- en oorwinteringsgebiede, wat gewoonlik duisende kilometers dek, gedurende die herfs en lente. Kroegkopganse reis vanaf Indiese oorwinteringsgebiede en hoë Asiatiese broeiplekke in China en Mongolië, wat beteken dat hulle die Himalaja-berge op pad moet oorsteek terwyl hulle so hoog as 7 290 m (23 917 voet) vlieg.

The animals have been shown to possess a number of specific physiological adaptations that may increase their performance relative to other species of geese when exposed to severe environmental hypoxia (inadequate oxygen supply). In particular, their heart and locomotor muscles contain more blood vessels.


Up, up and away

Somehow, these high flyers can exert themselves at exceptional altitudes. But what allows them to navigate the air up there? While these birds vary in size, they have one thing in common: a longer wingspan relative to their bodies, compared with birds that fly lower.

"That's something we consistently see," Scott said. "Longer wings are better for generating lift to keep the body aloft."

But it takes more than longer wings to navigate high altitudes, which come with enormous physical trials, Scott added.

"The first big challenge is that the air gets less dense," he said. "As they go higher, they have to flap harder to stay aloft, so their metabolic demands increase. The oxygen levels become more limited. At high altitudes, it gets colder, and they need to keep their bodies warm. And the air gets drier — they're more likely to lose water from breathing and evaporation, and be thirsty."

So what keeps these high fliers going? There are certainly physical adaptations that allow birds to reach exceptional heights, said Charles Bishop, a senior lecturer in zoology at the School of Biological Sciences at Bangor University in the United Kingdom.

Bishop, who studies high-flying bar-headed geese, told Live Science in an email that the geese do not appear to suffer from altitude sickness or from cerebral or pulmonary edema, "so that, unlike humans they do not feel ill when at high altitude."

The geese also hyperventilate to increase their oxygen intake while flying. This rapid breathing makes their blood more alkaline, a change that in humans affects circulation to the brain (which is why hyperventilating makes people feel dizzy or faint).

But geese are very tolerant of high pH (alkaline conditions), Bishop explained, so blood flow to the animals' brains and bodies remains healthy.

"Finally, the hemoglobin in their blood has quite a high affinity for oxygen binding," Bishop told Live Science. "Again, this maximizes oxygen uptake." [Quest for Survival: Photos of Incredible Animal Migrations]


Diet gave ducks and geese their odd beaks

You are free to share this article under the Attribution 4.0 International license.

The diets of ducks, geese, and other waterfowl have been the main evolutionary force behind the shape of their beaks, new research shows.

“Waterfowl have really interesting beaks relative to other birds,” says Aaron Olsen, a postdoctoral researcher in Brown University’s department of ecology and evolutionary biology. “They are very curvy with very diverse shapes.”

Waterfowl beaks vary along a duck-to-goose gradient (left to right), primarily because of differences in diet. (Credit: Aaron Olsen)

Working at the University of Chicago and the Field Museum of Natural History, Olsen sought to determine what accounts for that diversity.

He expected that diet might play a substantial role, but rather than just compare simple dietary categories with beak caliper measurements as many naturalists have, he engaged in a more detailed analysis. He carefully measured the 3D form of the beaks of 136 specimens of waterfowl, covering 51 species and 46 genera, including two extinct species. One fossil, Presbyornis, dates back tens of millions of years. Then he paired those measurements with detailed data that he gathered from the research literature on the diet of each bird.

Regardless of his expectation, if diet and beak shape had little to do with each other, the math would have yielded low correlations.

“What this analysis asks is, ‘What are the patterns of correlation between these two datasets?’,” Olsen says. “What’s nice about that is you are going in a little bit naively about the relationship between the two.”

But the mathematical result was a strong correlation between dietary preferences and beak shape. It makes physical sense, Olsen says.

Ducks, which primarily filter-feed little bugs and seeds from the water, have relatively long, wide-tipped bills that can bring in a lot of water. Geese, which evolved to prefer the leaves and roots of plants over filter feeding (though some still do), have shorter, narrower beaks that give geese a more forceful bite for pruning tough plant parts.

A Cape Barren goose skull (top) sports a rather different beak than that of a freckled duck (middle), which resembles the fossil Presbyornis (bottom). (Credit: Aaron Olsen)

The correlation is so strong, Olsen says, that diet likely dominates other influencers of beak shape that researchers have demonstrated, such as preening and shedding body heat. But Olsen says his analysis doesn’t preclude those factors from still having roles, too.

How birds evolved such crazy beaks

The data Olsen gathered, combined with several lines of prior research, also led him to hypothesize that the early ancestors of modern ducks, geese, and other waterfowl were duck-like. Geese-like beaks are newer phenomena, though they’ve evolved several times in several places.

First of all, Olsen says, a mathematical reconstruction he performed that accounted for modern waterfowl and the early ancestor in the waterfowl phylogenetic (or evolutionary family) tree, Presbyornis, showed that the duck-like beak is the most likely ancestral form. Moreover, the widespread emergence of grasses occurred after the origin of waterfowl, supporting a later origin for geese within waterfowl.

Swan’s springy neck inspires better drone cameras

The other extinct specimen whose bill Olsen surveyed, the fern-eating moa-nalos goose, may be a good example of the kind of transition he suspects played out multiple times over waterfowl’s evolutionary history. Other researchers have shown the moa-nalos likely had a duck-like ancestor, but after its ancestors ended up in Hawaii, it adapted to its final plant-eating status by evolving goose-like features over time.

All that said, Olsen acknowledges his assessment of waterfowl lineage remains an open hypothesis. He says he invites further research, even if it ultimately ruffles his feathers.

“I would love to see someone publish a paper and argue the opposite,” he says.

The National Science Foundation funded the research, which appears in the journal Funksionele Ekologie.


High Flying Geese

Photo Credit: Lip Kee [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons

The world&rsquos champion high-altitude migratory bird uses a unique &ldquoroller-coaster&rdquo flight strategy to save energy.

Transkripsie

How geese fly high. I&rsquom Bob Hirshon and this is Science Update.

Bar-headed geese migrate across the Himalayas twice a year. To find out how they accomplish this high-altitude journey, University of Bangor biologist Charles Bishop and his team outfitted the birds with heart rate monitors and accelerometers.

Biskop
The problem with flying high is that the air has become less dense and it&rsquos becoming more and more difficult to fly. If they were to go up and just fly along at that level, they&rsquore spending an awful lot of time at a very difficult, high-energy flight. What we actually discovered was that instead, these birds are regularly going up and then down again, and up and then down again, within the same flight. And we called this the roller coaster strategy, and this was kind of unexpected.

Bishop&rsquos team reports in the journal Wetenskap that even factoring in the costs of climbing back up again, this flight strategy saves the birds energy overall. I&rsquom Bob Hirshon, for AAAS, the science society.

Making Sense of the Research

The bar-headed goose, a pale grey bird with an orange beak and legs and two striking black bars on its head, lives in central Asia. Living as it does in an area that includes three very high mountain ranges, the bar-headed goose is widely believed to make the highest altitude migration on earth.

At high elevations, the atmosphere has less oxygen and the thin air provides less lift to aid bird flight. So, how does the bar-headed goose accomplish this difficult migration? That&rsquos what Charles Bishop and his team of researchers are trying to find out.

&ldquoWe wanted to know how high they flew, what were their flight paths and strategy with respect to the weather conditions, how difficult did they find these journeys, and how much energy did it require,&rdquo says Charles Bishop, a zoologist at Bangor University in the United Kingdom.

The old assumption was that bar-headed geese would fly to high altitudes relatively easily and then remain there during their flights, possibly benefitting from a tailwind. But by tracking a flock of bar-headed geese from Mongolia to India, researchers found that the birds descend to a lower altitude before flying to new heights. Their study, published in Wetenskap 16th January 2015, shows that the geese perform a sort of roller coaster ride through the mountains, essentially tracking the underlying terrain even if this means repeatedly giving up altitude only to have to regain it later.

How does this up and down flying strategy help the birds? Flying at progressively higher altitudes is very difficult as the decreasing air density reduces the bird's ability to produce the lift and thrust required to maintain flight. The birds also face the problem of reduced oxygen availability as the atmospheric pressure and oxygen levels drop in the higher elevations.

Professor Pat Butler from the University of Birmingham said the geese would seek out the side of valleys in order to swerve higher&mdashin the way a roller coaster might swoop around a corner and upwards. The roller coaster pattern helps birds conserve energy as they migrate over the Himalayas.

&ldquoDuring these moments,&rdquo says Butler, &ldquoit seems likely that the bar-headed geese are flying on the windward side of a valley wall. This would give them the best opportunity of obtaining assistance from wind that is deflected upwards by the ground, providing additional rates of ascent with either a reduction in their energetic costs or at least no increase.&rdquo

Hoe is dit moontlik? "The physiology of bar-headed geese has evolved in a number of ways to extract oxygen from the thin air at high altitudes," said Dr. Graham Scott, another member of the study team. "As a result, they are able to accomplish something that is impossible for most other birds."

Now try and answer these questions:

  1. Why is flying at high altitudes more difficult than flying at low altitudes?
  2. What did the scientists do to track the birds&rsquo flight pattern?
  3. Before this research, how did scientists think that bar-headed geese were able to fly at such altitudes?
  4. Why is the strategy used by the birds described as a roller coaster maneuver?
  5. How does this strategy help the birds save energy for the strenuous flight?
  6. In addition to this unique flight strategy, what else helps the geese fly such long distances at high altitudes?

Read Feather Biology to learn more about how birds fly.

Check out the How Do Birds Fly animation to learn more about different techniques birds use for flight.

Gaan verder

In addition to the resources mentioned, you can extend the concepts in this lesson by helping your students explore the role that variation within a species plays in Feathers: The Evolution of a Natural Miracle.

To learn more about bird migratory patterns and the methods researchers use to study them, see Bird Populations.


Dier Diversiteit Web

Canada geese ( Branta canadensis ) are native to Canada, the United States, and Mexico. Although their range covers much of North America, Canada geese generally winter in the southern portion of the continent. Despite their North American origins, Canada geese have been introduced to habitats around the globe. Both intentional introduction and vagrancy are responsible for their introduction to much of Europe, Australia, and parts of Asia, such as Japan, Korea, and Russia. ("Branta canadensis", 2013 Birdlife International, 2012 Jansson, et al., 2008)

Habitat

Canada geese prefer open, grassy habitats. Areas with obstructions such as tall grass and shrubs are generally avoided because they may disguise predators. This species prefers to live near water including ponds, marshes, rivers, or coastlines. Canada geese can be successful at nearly all elevations, from coastal to alpine regions. Populations of these birds have become well established in urban and suburban areas where grassy lawns are maintained. They are also often seen grazing in agricultural land. (Conover, 1991 Jansson, et al., 2008 Johnson, 2012 Robinson, 2005 "Canada Goose (Branta canadensis)", 2013)

  • Habitat Regions
  • temperate
  • aardse
  • varswater
  • Terrestriële biome
  • toendra
  • savanna or grassland
  • woud
  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams
  • coastal
  • Wetlands
  • marsh
  • Other Habitat Features
  • stedelik
  • suburban
  • riparian
  • estuarine

Physical Description

Canada geese can be identified by their long black head and neck, and their bill, which has a distinctive white mark near their chin. Their plumage has varying shades of brown-grey feathers on their dorsal region, and typically a cream or white color on their belly and rump. This species experiences a small degree of sexual dimorphism, where males are slightly larger than their female counterpart, but both weigh between 3 to 10.9 kg. Canada geese have a height of 76 to 110 cm and a wingspan of 1.3 to 1.7 m. Despite small size differences between the sexes, they appear similar. Goslings are yellow with grey-green feathers on their dorsal region and sometimes head, depending on the subspecies. They are born with black bills and feet. Their bill has lamella (comb-like ridges) around the outside edge, to aid feeding. There are seven subspecies, which are distinguished by size, plumage color, white cheek marks, or the presence of a white collar. Among the seven subspecies, the largest is Branta canadensis maxima, and generally weighs about 6.4 kg. ("Branta canadensis", 2013 Jansson, et al., 2008 Johnson, 2012 "Canada Goose Branta canadensis", 2013 "Canada Goose", 2013 "Canada Goose", 2012 "Canada Goose (Branta canadensis)", 2013)

  • Other Physical Features
  • endotermies
  • bilaterale simmetrie
  • Sexual Dimorphism
  • male larger
  • Range mass 3 to 10.9 kg 6.61 to 24.01 lb
  • Range length 76 to 110 cm 29.92 to 43.31 in
  • Range wingspan 1.3 to 1.7 m 4.27 to 5.58 ft

Reproduksie

Male geese are referred to as "ganders" and female geese are simply known as "geese." Pairs often select each other based on a similarity in size, which is known as "assortative mating". Often remaining paired for life, Canada geese are monogamous. If one mate dies, the remaining partner finds another mate. Due to their social nature, pairs of Canada geese with goslings often join other parents in groups called "crèches". They remain together, sometimes until the next breeding season. (Jansson, et al., 2008 "Canada Goose (Branta canadensis)", 2013)

Breeding occurs yearly, generally from April to May, but may extend into June in colder climates. Females are responsible for nest formation and seem to have a preferred mating site they return to each mating season. Upon finding a suitable location, one that is near water and has a favorable vantage point, the female pulls together twigs and grasses to form a nest and insulates it with feathers or down. Although Canada geese reach sexual maturity at two years of age, the first incidence of breeding usually does not occur until at least age three. Canada geese raise one brood each mating season and only re-nest if their initial effort has been unsuccessful. They lay anywhere from 2 to 10 eggs. Each egg is laid approximately a day and a half apart and incubation begins once the final egg is laid. Females occasionally rotate the eggs during incubation. The eggs take 28 to 30 days to hatch. Goslings use an "egg tooth," a hard, sharp, tooth-like projection on their bill, to help them leave the egg. When the eggs have hatched, the geese often form groups with other parents and their goslings. Goslings are precocial and can leave the nest as quickly as 24 hours after hatching. This allows geese and ganders to lead goslings to food and water shortly after hatching. Despite their ability to leave the nest quickly, fledging does not occur until an average of 44 days after hatching. At some point during the breeding season, Canada geese molt their feathers and are temporarily unable to fly. This period lasts about a month, during which they are particularly vulnerable to predation. (Jansson, et al., 2008 Johnson, 2012 Robinson, 2005 "Canada Goose (Branta canadensis)", 2013)

Hybridization between Canada geese and other species, often greylag geese, and sometimes snow geese or barnacle geese have occurred in captivity, but it is thought to be less common in nature. However, the occurrences of hybridization in nature may be explained by brood amalgamation (adoption of orphan chicks) of some goose species, or the nest parasitism displayed by some geese. The adopted offspring are raised to be attracted to the fostering goose species, not their own. (Jansson, et al., 2008 "Canada Goose (Branta canadensis)", 2013)

  • Key Reproductive Features
  • iteroparous
  • seasonal breeding
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • seksuele
  • bevrugting
  • oviparous
  • Breeding interval Canada geese breed once yearly.
  • Breeding season These birds breed from April to May.
  • Range eggs per season 2 to 10
  • Average eggs per season 5 AnAge
  • Range time to hatching 28 to 30 days
  • Range fledging age 40 to 48 days
  • Range time to independence 1 to 1 years
  • Range age at sexual or reproductive maturity (female) 2 to 3 years
  • Average age at sexual or reproductive maturity (female) 3 years
  • Range age at sexual or reproductive maturity (male) 2 to 3 years
  • Average age at sexual or reproductive maturity (male) 3 years

Among Canada geese, parental investment is high during the first year of their offspring's life. Before the eggs have been laid and during incubation, both males and females are protective of the nest. Once the eggs hatch, males become responsible for defending the nest. Males can be very aggressive against predators and other geese during the mating season. The goslings are relatively well-developed when they hatch, and after only 7 to 10 weeks, they can both fly and find food for themselves. Despite their capabilities, juveniles stay with their parents until after they return from spring migration, when the next breeding season begins. (Johnson, 2012 Jansson, et al., 2008)

  • Parental Investment
  • precocial
  • male parental care
  • female parental care
  • pre-fertilization
    • provisioning
    • protecting
      • manlik
      • vroulik
      • provisioning
        • vroulik
        • manlik
        • provisioning
          • manlik
          • vroulik
          • manlik
          • vroulik
          • protecting
            • manlik
            • vroulik

            Lifespan/Longevity

            It is difficult to determine the average life expectancy for Canada geese. In captivity, the longest lived goose was 80 years old. In the wild, the oldest goose was reportedly 30 years and 4 months old. To have such a long life in the wild is extraordinary the life expectancy for most wild geese is 12 years. (Johnson, 2012 Jansson, et al., 2008 Robinson, 2005)

            • Range lifespan
              Status: wild 30 (high) years
            • Range lifespan
              Status: captivity 80 (high) years
            • Typical lifespan
              Status: wild 10 to 24 years
            • Average lifespan
              Status: wild 12 years

            Gedrag

            The v-formation used by Canada geese in flight is very energy efficient, as is flying with the wind. This arrangement during flight is called a "wedge" or "skein." The lead position in the "wedge" is rotated because it is the most taxing flight position in terms of energy usage. This technique allows Canada geese to cover up to 2,400 km in a single day of flight. Flocks of geese are often vocal and communicate with each other during flight. ("Branta canadensis", 2013 Johnson, 2012 Jansson, et al., 2008)

            Home Range

            Giving a true description of the home range for all Canada geese is difficult. In some populations, a lone female has a mean home range of 25 km2. The home range size increases as the amount of geese in the population increases. Geese that have become residents of urban or suburban areas have smaller home ranges than birds that participate in migration. There are multiple factors that keep certain populations in one location. With the prevalence of manicured lawns, geese in temperate regions have access to food and a desirable habitat in the winter. Also, the lack of predators in urban environments encourages Canada geese to remain in one location. Lastly, migration is taught to offspring by the parents. If the parental pair does not migrate, the offspring of the couple will become non-migratory. The birds that do migrate spend spring in their northern breeding territory and winter in their southern wintering range. (Johnson, 2012 Birdlife International, 2012 Cross, 2013 Groepper, et al., 2008 Link, 2013)

            Communication and Perception

            Canada geese are known for their honking noise. During flight, they honk to communicate with each other. The typical honk associated with Canada geese is from the gander. The goose has a shorter, higher pitched call. They also hiss when they feel threatened. (Johnson, 2012 Jansson, et al., 2008 McClary, 2004)

            • Communication Channels
            • acoustic
            • Perception Channels
            • visual
            • tactile
            • acoustic
            • chemiese

            Voedselgewoontes

            A proper diet for Canada geese should be high in protein and energy. Their diet can generally be categorized as herbivorous and consists mainly of leaves, grass, seeds, berries, algae, and roots. The lamella on the edge of their bill helps during grazing, when grass is removed by making a jerking motion with their head. Plants containing high amounts of secondary metabolites are avoided, which helps prevent digestive issues and poisoning. Occasionally, aquatic invertebrates, insects, small fish, crustaceans, and mollusks may be dined upon, generally during juvenile development, when rearing goslings, or during breeding, where more nutrients are necessary. If environmental conditions prevent food from being obtained, Canada geese can go up to 30 days without food. (Conover, 1991 Jansson, et al., 2008 Johnson, 2012 "Canada Goose Branta canadensis", 2013 "Canada Goose", 2012 "Canada Goose (Branta canadensis)", 2013)

            • Primary Diet
            • herbivore
              • folivore
              • granivore
              • algivore
              • Animal Foods
              • vis
              • insekte
              • mollusks
              • aquatic crustaceans
              • other marine invertebrates
              • Plant Foods
              • blare
              • roots and tubers
              • seeds, grains, and nuts
              • alge

              Predasie

              Due to the large size of Canada geese, they do not have many predators. If they feel threatened, honking and hissing will ensue, often joined with hostile movements. Unattended eggs and goslings are much more vulnerable and may be preyed upon by other birds such as gulls, ravens, and crows. Other predators include foxes, wolves, coyotes, bears, dogs, skunks, and raccoons. The vast majority of deaths are caused by humans as Canada geese are considered game birds. (Johnson, 2012 "Canada Goose (Branta canadensis)", 2013)

              • Known Predators
                • coyotes (Canis latrans)
                • humans (Homo sapiens)
                • gulls (Laridae)
                • ravens (Corvus)
                • crows (Corvus)
                • skunks (Mephitidae)
                • racoons (Procyon lotor)
                • arctic foxes (Vulpes lagopus)
                • red foxes (Vulpes vulpes)
                • grey wolves (Canis lupus)
                • bears (Ursidae)
                • domestic dogs (Canis lupus familiaris)

                Ecosystem Roles

                Canada geese are important in their ecosystem as they distribute seeds from the various plants they consume. Canada geese can also carry many parasites. Gizzard worms are common avian parasites and Canada geese are no exception. They can also be infected by the bacterium that causes avian cholera, chlamydiosis, avian botulism, and salmonella. Duck virus enteritis (DVE) is caused by a herpes virus that is thought to be transferred through goose droppings. They can also be victim to aspergillosis, a fungal infection that occurs in birds. (Johnson, 2012 "Duck Virus Enteritis", 2013 "Canada Goose (Branta canadensis)", 2013)

                Economic Importance for Humans: Positive

                Canada geese were not originally introduced to Europe for hunting, but it quickly became a main purpose for introduction in places like Denmark, Russia, and Sweden. This not only provides recreational activity, but geese can provide food for the hunters. The down feathers from their plumage are also of economic importance, they are used in coats, pillows, blankets, and in numerous other items. (Jansson, et al., 2008)

                Economic Importance for Humans: Negative

                Canada geese are sometimes viewed as pests because of their tendency to graze on manicured lawns, which leads to unsanitary defecation and potential damage to the ground covering. Large flocks of geese can compact the soil, making it less suitable for further growth. Trying to deter Canada geese from foraging on lawns may have a significant economic cost for some, including country clubs, lawn enthusiasts, and the agricultural community. Canada geese can carry many diseases including: avian influenza, avian cholera, botulism, salmonellosis, chlamydiosis, duck virus enteritis (DVE or duck plague), aspergillosis, and various parasites. Geese can carry these and other parasites, bacteria, and viruses in their fecal matter and spread it to humans or other animals. For this reason, their unsanitary fecal matter can be a problem for the management of water sources. Large flocks of Canada geese can be a hazard for airplanes. The geese can cause take off and landing delays due to their presence on the runway. In extreme cases, a goose (or many geese) can enter the engine and cause the plane to crash. The time spent managing waterfowl activity near airports and control towers, as well as aircraft loses, is costly. But the cost of human lives as a result of these accidents is immeasurable. (Conover, 1991 Jansson, et al., 2008)

                Conservation Status

                In 1918, the US Migratory Bird Act took effect, making it illegal to hunt, capture, or kill birds in migration across the United States. As a result, Canada geese are game birds that can only be hunted during hunting season or with a special permit. Despite this caveat, Canada geese are often killed without permits because the geese are seen as pests in urban areas. Canada geese are generally seen as a species of little or no conservation concern. Although some measures are being taken to control their population, as a whole, the population seems to be increasing and is already very large. (Johnson, 2012)

                • IUCN Red List Least Concern
                  Meer inligting
                • IUCN Red List Least Concern
                  Meer inligting
                • US Migratory Bird Act Protected
                • US Federal List No special status
                • CITES Appendix I
                • State of Michigan List No special status

                Other Comments

                Currently, seven subspecies of Canada geese have been recognized: Branta canadensis Canadensis (Atlantic Canada goose), B. c. fulva (Vancouver Canada goose), B. c. interior (Hudson Bay Canada goose), B. c. maxima (giant Canada goose), B. c. moffitti (Moffitt's or Great Basin Canada goose), B. c. occidentalis (dusky Canada goose), and B. c. parvipes (lesser Canada goose). Branta canadensis canadensis is thought to be the nominate subspecies. Although B. c. maxima is the largest subspecies, B. c. moffitti is similar in size and coloration, the most distinct difference between the species is the white mark on the forehead of B. c. moffitti . In 2004 cackling geese were separated from Canada geese due to mitochondrial DNA evidence. ("Branta canadensis", 2013 Sibley, 2010 "Canada Goose (Branta canadensis)", 2013)

                Bydraers

                Fauna Yarza (author), Sierra College, Jennifer Skillen (editor), Sierra College, Leila Siciliano Martina (editor), Animal Diversity Web Staff.

                Woordelys

                Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

                living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

                body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

                living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

                gebruik klank om te kommunikeer

                met liggaamsimmetrie sodanig dat die dier in een vlak in twee spieëlbeeldhelftes verdeel kan word. Diere met bilaterale simmetrie het dorsale en ventrale sye, sowel as anterior en posterior punte. Synapomorfie van die Bilateria.

                gebruik reuke of ander chemikalieë om te kommunikeer

                the nearshore aquatic habitats near a coast, or shoreline.

                helpers provide assistance in raising young that are not their own

                diere wat metabolies gegenereerde hitte gebruik om liggaamstemperatuur onafhanklik van omgewingstemperatuur te reguleer. Endotermie is 'n sinapomorfie van die Mammalia, hoewel dit moontlik in 'n (nou uitgestorwe) sinapsied-voorouer ontstaan ​​het, onderskei die fossielrekord nie hierdie moontlikhede nie. Konvergent by voëls.

                an area where a freshwater river meets the ocean and tidal influences result in fluctuations in salinity.

                parental care is carried out by females

                union of egg and spermatozoan

                an animal that mainly eats leaves.

                A substance that provides both nutrients and energy to a living thing.

                forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

                mainly lives in water that is not salty.

                an animal that mainly eats seeds

                An animal that eats mainly plants or parts of plants.

                referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

                nageslag word in meer as een groep (werpsels, kloue, ens.) en oor verskeie seisoene (of ander tydperke wat gasvry is vir voortplanting) geproduseer. Iteroparous diere moet per definisie oor veelvuldige seisoene (of periodieke toestandsveranderinge) oorleef.

                parental care is carried out by males

                marshes are wetland areas often dominated by grasses and reeds.

                makes seasonal movements between breeding and wintering grounds

                Having one mate at a time.

                met die vermoë om van een plek na 'n ander te beweeg.

                the area in which the animal is naturally found, the region in which it is endemic.

                found in the oriental region of the world. In other words, India and southeast Asia.

                voortplanting waarin eiers vrygestel word deur die vroulike ontwikkeling van nageslag vind buite die moeder se liggaam plaas.

                Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

                breeding is confined to a particular season

                voortplanting wat die kombinasie van die genetiese bydrae van twee individue, 'n man en 'n vrou, insluit

                associates with others of its species forms social groups.

                living in residential areas on the outskirts of large cities or towns.

                uses touch to communicate

                that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

                A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

                A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

                A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

                A terrestrial biome with low, shrubby or mat-like vegetation found at extremely high latitudes or elevations, near the limit of plant growth. Soils usually subject to permafrost. Plant diversity is typically low and the growing season is short.

                living in cities and large towns, landscapes dominated by human structures and activity.

                uses sight to communicate

                young are relatively well-developed when born

                Verwysings

                2013. " Branta canadensis " (On-line). ITIS (Integrated Taxonomic Information System). Accessed April 07, 2013 at http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=174999.

                University of Illinois Board of Trustees. 2013. "Canada Goose ( Branta canadensis )" (On-line). Living with Wildlife in Illinois. Accessed May 09, 2013 at http://web.extension.illinois.edu/wildlife/directory_show.cfm?species=canadagoose.

                National Geographic Society. 2013. "Canada Goose Branta canadensis " (On-line). Accessed May 07, 2013 at http://animals.nationalgeographic.com/animals/birds/canada-goose/.

                Seattle Audubon Society. 2013. "Canada Goose" (On-line). Bird Web. Accessed May 10, 2013 at http://www.birdweb.org/birdweb/bird/canada_goose.

                The Royal Society for the Protection of Birds. 2012. "Canada Goose" (On-line). The Royal Society for the Protection of Birds. Accessed May 07, 2013 at http://www.rspb.org.uk/wildlife/birdguide/name/c/canadagoose/index.aspx.

                State of Michigan. 2013. "Duck Virus Enteritis" (On-line). Michigan Department of Natural Resources. Accessed May 12, 2013 at http://www.michigan.gov/dnr/0,4570,7-153-10370_12150_12220-26644--,00.html.

                Birdlife International, 2012. " Branta canadensis (Canada Goose)" (On-line). IUCN Rooi Lys van Bedreigde Spesies. Accessed May 07, 2013 at http://www.iucnredlist.org/details/22679935/0.

                Conover, M. 1991. Herbivory by Canada geese: diet selection and effect on lawns. Ecological Applications , 1/2: 231-236. Accessed March 16, 2013 at http://www.esajournals.org/doi/abs/10.2307/1941816.

                Cross, T. 2013. "Why have Canadian Geese stopped migrating?" (On-line). Examiner.com. Accessed August 16, 2013 at http://www.examiner.com/article/why-have-canadian-geese-stopped-migrating.

                Groepper, S., P. Gabig, M. Vrtiska, J. Gilsdorf, S. Hygnstrom, L. Powell. 2008. Population and spatial dynamic of resident Canada geese in southeastern Nebraska. Human-Wildlife Conflicts , 2/2: 271-278.


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